﻿// This is an open source non-commercial project. Dear PVS-Studio, please check it.
// PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com

// ReSharper disable CheckNamespace
// ReSharper disable ClassNeverInstantiated.Global
// ReSharper disable CommentTypo
// ReSharper disable IdentifierTypo
// ReSharper disable InconsistentNaming
// ReSharper disable StringLiteralTypo
// ReSharper disable UnusedParameter.Local

/* Cast.Enumerable.cs --
 * Ars Magna project, http://arsmagna.ru
 */

#nullable enable

namespace AM.Memory.Collections.Linq;

internal class CastExprEnumerable<T>
    : IPoolingEnumerable<T>
{
    private int _count;

    private IPoolingEnumerable? _src;

    public CastExprEnumerable<T> Init (IPoolingEnumerable src)
    {
        _src = src;
        _count = 0;
        return this;
    }

    public IPoolingEnumerator<T> GetEnumerator()
    {
        _count++;
        return Pool<CastExprEnumerator>.Get().Init (_src!.GetEnumerator(), this);
    }

    private void Dispose()
    {
        if (_count == 0) return;
        _count--;
        if (_count == 0)
        {
            _src = default;
            Pool<CastExprEnumerable<T>>.Return (this);
        }
    }

    internal class CastExprEnumerator : IPoolingEnumerator<T>
    {
        private IPoolingEnumerator? _src;
        private CastExprEnumerable<T>? _parent;

        public CastExprEnumerator Init (IPoolingEnumerator src, CastExprEnumerable<T> parent)
        {
            _src = src;
            _parent = parent;
            return this;
        }

        public bool MoveNext()
        {
            return _src!.MoveNext();
        }

        public void Reset()
        {
            _src!.Reset();
        }

        object IPoolingEnumerator.Current => Current!;

        public T Current => (T)_src!.Current;

        public void Dispose()
        {
            _parent?.Dispose();
            _parent = null;
            _src?.Dispose();
            _src = default;
            Pool<CastExprEnumerator>.Return (this);
        }
    }

    IPoolingEnumerator IPoolingEnumerable.GetEnumerator() => GetEnumerator();
}
